Data collection

For the X-ray diffraction data collection we have the Bruker Microstar X8 Proteum Cu-rotating anode X-ray generator equipped with a Helios MX focusing optics and kappa goniometer (Figure 1 and 2). The wavelength of the X-ray beam is 1.5418Å. The data is collected with a Platinum 135 CCD detector. Data collection is carried out at room temperature or with cryo-cooled crystals. The cryounit is an Oxford Cryostream 700 series. Data collection at cryo temperature is usually done at 100K (30 degrees above the boiling temperature of liquid nitrogen).

The size of the beam at the crystal is 160 micron (FWHM). The optimal size of the crystals is 100-200 micrometer in diameter. The total flux is 0.6x1010 photons/sec. There are three collimators, providing beam divergence of 7, 5, and 3 mrad (10mrad corresponds to a beam divergence of 0.6 degrees). For large cell dimensions and high quality data it is best to use the 3mrad collimator. In that case the total flux is about 3 fold less as compared to the flux obtained with the 7mrad collimator. Data processing is done with the Proteum2 software.

Figure 1. Bruker Microstar X8 Proteum equipped with Kappa goniometer.

Figure 2. Kappa goniometer.

The kappa axis is at 50o with respect to the ω-axis. The crystal can be rotated about Φ and ω, allowing for an efficient collection of a complete and highly redundant dataset. The detector can be rotated about 2θ, allowing for collecting data to high resolution.

Diffraction data is also regularly collected at synchrotrons. Occasionally, the data collection is done remotely, from our laboratory. For these data collection efforts we maintain storage dewars and transport dewars. For the freezing of crystals a range of loops are available, including bar-coded loops, which are in particular important for synchrotron visits. The data processing is done routinely with XDS or iMOSFLM.

For data tracking we use and develop further in collaboration with Diamond Light Source Oxford, UK and Instruct the xtalPiMS software package (Figure3).